MacBook Pro IPv6 Issues

I’ve had this issue with my MacBook for a while now, where – after it wakes up from sleep – I can’t connect to the internet for a couple of minutes. Wifi is on and working, mind you, but I can’t open any websites or sync emails. It’s annoying as hell.

Linux laptop running Ubuntu? Totally fine!

Yesterday I tried to debug it once again, and used Claude for rubber ducking my ideas/suspicions.

I do not have any in-depth knowledge about networking, so I went through all the wifi settings and finally found “IPv6 configuration”. As it turned out, when selecting “link-local only” (instead of automatic) the problems were gone.

Claude’s explanation:

This is a known macOS quirk that’s been around for several versions. What’s happening is:

On Linux: After sleep/wake, the network stack properly renegotiates everything - new DHCP lease, router advertisements, neighbor discovery, etc.

On macOS: After sleep/wake, macOS tries to be “smart” by preserving network state to reconnect faster, but sometimes this cached state becomes stale or corrupted, especially with IPv6. It keeps the old IPv6 routes/addresses but they no longer work properly.

I love the “tries to be smart” remark. 😂

Claude also gave me some references to Apple forum discussions about the issue, so its explanation sounds reasonable to me.

Also, I am sure the router I am using (Fritz!Box 6591 Cable) and our provider (Vodafone) have something to do with it, because I never had the issue at the office for example. So I still might dig a little deeper – but for now I am just glad I can use my MacBook right after it wakes up from sleep.

PS: Not having IPv6 routing available should not be that big of an issue – at least for the time being, and not worth waiting a couple of minutes after waking my MacBook from sleep… Please let me know, if I am missing something important here. 🙂

PPS: This might also be of interest: I had this issues with macOS 26 and 15.